The aim of a power allocation scheme is to dynamically allocate the RF power to the UE:s in a cell in order to balance the downlink co-channel interference in multi-cell environment. This is particularly important in a multi-cell orthogonal frequency division multiple access (OFDMA) based environment with tight frequency reuse, e.g. reuse 1 or reuse 3.
In an OFDMA based system the available bandwidth is sub-divided into several chunks of frequencies. A chunk is usually a two-dimensional radio resource, defined in both time and frequency domain and comprises of orthogonal sub-carriers. Each UE estimates the downlink channel quality on each chunk and reports the measured quality, e.g. a channel quality indicator (CQI), to the network. The CQI can be measured by an UE on pilot symbols. Downlink channel quality measurements can use any other suitable measurable signal that can depict the downlink instantaneous channel quality. Based on the reported CQI a radio network controller (RNC) dynamically allocates the chunks to be used for transmission of data to the UE:s in the downlink. To allocate chunks the RNC uses any conventional frequency allocation scheme. Base stations, also referred to as access points (AP:s), transmits on the selected chunks using a certain power level which is determined by a conventional power control scheme managed by the RNC.